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Degree of Dissociation

Anhydrous cal...

Question

Anhydrous calcium chloride is often used as a desiccant. In the presence of excess of $C a C l_{2}$ , the amount of the water taken up is governed by $K_{P} = 6.4 \times 10^{85}$ for the following reaction at room temperature, $C a C l_{2} (s) + 6 H_{2} O (g) ⇌ C a C l_{2} . 6 H_{2} O (s) .$ What is the equilibrium vapour pressure of water in a closed vessel that contains $C a C l_{2} (s) ?$

A

5 \times 10^{- 13} a t m

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B

5 \times 10^{- 15} a t m

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C

5 \times 10^{- 14} a t m

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D

5 \times 10^{- 11} a t m

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Solution

The correct option is B $5 \times 10^{- 15} a t m$
Given reaction,
$C a C l_{2} (s) + 6 H_{2} O (g) ⇌ C a C l_{2} . 6 H_{2} O (s)$
$K_{p} = 6.4 \times 10^{85} K_{p} = \frac{1}{(p_{H_{2} O})^{6}}$
$\Rightarrow \frac{1}{(p_{H_{2} O})^{6}} = 6.4 \times 10^{85}$
$\Rightarrow (p_{H_{2} O})^{6} = \frac{1}{6.4 \times 10^{85}}$
$\Rightarrow (p_{H_{2} O})^{6} = \frac{1}{6.4 \times 10^{84} \times 10}$
$\Rightarrow (p_{H_{2} O})^{6} = \frac{1}{64 \times 10^{84}}$
$\Rightarrow (p_{H_{2} O})^{6} = \frac{1}{(2)^{6} \times (10^{14})^{6}}$
$\Rightarrow p_{H_{2} O} = \frac{1}{(2) \times (10^{14})}$

$p_{H_{2} O} = 0.5 \times 10^{- 14} a t m$
$p_{H_{2} O} = 5 \times 10^{- 15} a t m$

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Similar questions

Q. Anhydrous calcium chloride is often used as a dessicant. In the presence of excess of

C a C l_{2}

, the amount of the water taken up is governed by

K_{p} = 6.4 \times 10^{8} 5

for the following reaction at room temperature,

C a C l_{2} (s) + 6 H_{2} O (g) ⇌ C a C l_{2} .6 H_{2} O (s) .

What is the equilibrium vapour pressure of water in a closed vessel that contains

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Degree of Dissociation

Standard XII Chemistry

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